The H-Man (1958)

A drug dealer named Misaki disappears leaving only his clothes. The next day the police go to question his girlfriend, singer Chikako Arai, and she informs them that she doesn't have any information on where he is. Later that evening one of his associates comes by to try to beat the truth out her. After he leaves he disappears in the same way that Misaki did.

A short time later, a young scientist named Masada informs the police that there was a similar case of people disappearing and leaving just their clothes on a seemingly abandoned ship that was found by a group of fishermen who say that three members of their crew were dissolved by a living liquid that was created when the crew of the ghost ship went through a radioactive cloud. The police are skeptical at first but when they witness the liquid creature, now called the H-man, kill three people, including a policeman at a the nightclub where Chikako worked they now believe him. Now the police must not only find the criminal gang, but figure out a way to destroy the H-men before they kill all the citizenry of Tokyo.